Abstract

The characteristic X-rays produced by the interactions of the electron beam with the sample in a scanning electron microscope (SEM) are usually captured with a variable-energy detector, a process termed energy dispersive spectrometry (EDS). The purpose of this work is to exploit inverse simulations of SEM-EDS spectra to enable rapid determination of sample properties, particularly elemental composition. This is accomplished using penORNL, a modified version of PENELOPE, and a modified version of the traditional Levenberg Marquardt nonlinear optimization algorithm, which together is referred to as MOZAIK-SEM. The overall conclusion of this work is that MOZAIK-SEM is a promising method for performing inverse analysis of X-ray spectra generated within a SEM. As this methodology exists now, MOZAIK-SEM has been shown to calculate the elemental composition of an unknown sample within a few percent of the actual composition.

@article{osti_1339398,
title = {Rapid evaluation of particle properties using inverse SEM simulations},
author = {Bekar, Kursat B and Miller, Thomas Martin and Patton, Bruce W and Weber, Charles F},
abstractNote = {The characteristic X-rays produced by the interactions of the electron beam with the sample in a scanning electron microscope (SEM) are usually captured with a variable-energy detector, a process termed energy dispersive spectrometry (EDS). The purpose of this work is to exploit inverse simulations of SEM-EDS spectra to enable rapid determination of sample properties, particularly elemental composition. This is accomplished using penORNL, a modified version of PENELOPE, and a modified version of the traditional Levenberg Marquardt nonlinear optimization algorithm, which together is referred to as MOZAIK-SEM. The overall conclusion of this work is that MOZAIK-SEM is a promising method for performing inverse analysis of X-ray spectra generated within a SEM. As this methodology exists now, MOZAIK-SEM has been shown to calculate the elemental composition of an unknown sample within a few percent of the actual composition.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2017},
month = {Sun Jan 01 00:00:00 EST 2017}
}

This report is the final deliverable of a 3 year project whose purpose was to investigate the possibility of using simulations of X-ray spectra generated inside a scanning electron microscope (SEM) as a means to perform quantitative analysis of the sample imaged in the SEM via an inverse analysis methodology. Using the nine point Technology Readiness Levels (TRL) typically used by the US Department of Defense (DOD) and the National Aeronautics and Space Administration (NASA), this concept is now at a TRL of 3. In other words, this work has proven the feasibility of this concept and is ready tomore » be further investigated to address some of the issues highlighted by this initial proof of concept.« less

A technique employing SEM-based automated image analysis (AIA) has been developed for assessing the association of mineral particles with coal, and thus the cleanability of that coal, when the characteristics of the separation process are known. Data resulting from AIA include the mineral distribution by particle size, mineral phase, and extent of association with coal. This AIA technique was applied to samples of {minus}325 mesh ({minus}44 {mu}m) coal from the Indiana No. 3, Upper Freeport, and Sunnyside (UT) seams. The coals were subjected to cleaning by float-sink separations at 1.3, 1.4, 1.6, and 1.9 specific gravity and by froth flotation.more » For the three coals, the float-sink procedure at a given specific gravity produced different amounts of clean coal, but with similar ash content. Froth flotation removed much less ash, yielding a product ash content of {approximately}8% for the Upper Freeport coal, regardless of recovery, while reducing the ash content to less than 5% for the other two coals. The AIA results documented significantly more association of minerals with the Upper Freeport coal, which thus led to the poor ash reduction.« less

The compositions of individual synthetic fluid inclusions in the systems NaCl-KCl, NaCl-CaCl/sub 2/, and NaCl-KCl-CaCl/sub 2/ have been successfully determined by EDA of precipitates produced during thermal decrepitation. Inclusions containing known mixtures of 20 wt% total salinity were synthesized by healing fractures in natural quartz at 600/sup 0/C and 7 Kb for 10 days. The two-phase, daughter-free inclusions homogenized at 170 +/- 10/sup 0/C, began to decrepitate at 280-300/sup 0/C, and by 350/sup 0/C a significant number of decrepitates had formed on the polished surface. Peak areas generated by EDA (raster mode) of these decrepitates were standardized using both singlemore » salt standards and mixed salt standards evaporated to dryness in a vacuum. Although the mixed salts better approximate the decrepitate compositions, difficulties were encountered in producing micro-scale homogeneity and the single salts yielded more reliable results. Three different solutions from each system were run and in all 9 samples the average values of 10-20 decrepitates fell within 6 wt % of the original chemistry suggesting that the decrepitates were chemically representative of their precursor inclusions. In all but one of the 9 samples (NK2) the known composition was within one standard deviation of the decrepitate average. Results form the 2 component systems are tabulated.« less

A technique employing SEM-based automated image analysis (AIA) has been developed for assessing the association of mineral particles with coal, and thus the cleanability of that coal, when the characteristics of the separation process are known. Data resulting from AIA include the mineral distribution by particle size, mineral phase, and extent of association with coal. This AIA technique was applied to samples of -325 mesh (-44 ..mu..m) coal from the Indiana No. 3, Upper Freeport, and Sunnyside (UT) seams. The coals were subjected to cleaning by float-sink separations at 1.3, 1.4, 1.6, and 1.9 specific gravity and by froth flotation.more » For the three coals, the float-sink procedure at a given specific gravity produced different amounts of clean coal, but with similar ash content. Froth flotation removed much less ash, yielding a product ash content of --8% for the Upper Freeport coal, regardless of recovery, while reducing the ash content to less than 5% for the other two coals. The AIA results documented significantly more association of minerals with the Upper Freeport coal, which thus led to the poor ash reduction.« less